Driver side airbag modules, which include an airbag cushion and an airbag module cover, are normally positioned within a hub of a steering wheel of a motor vehicle. An annular retainer ring secures the airbag cushion to the airbag module, and a cushion strap holds the airbag cushion in a folded position prior to deployment. Both the airbag module cover and cushion strap include a tear seam or weakened portion for allowing the airbag cushion to break through and fully deploy during a collision or rapid deceleration of the motor vehicle.
The hub of the steering wheel happens to be the same area which conventionally includes the horn switch. Accordingly, the airbag module cover must additionally serve to actuate the horn switch. A horn switch assembly normally includes suitable components such as a membrane type horn switch and a backing plate for example, and the horn switch assembly is attached to an inner surface of a horn actuation face of the airbag module cover by ultrasonic welding or heat staking.
Mounting the horn switch assembly to the airbag module cover by ultrasonic welding or heat staking is a time consuming assembly process that increases the cost of manufacturing the airbag module. In addition, the horn switches are sometimes damaged by heat staking, requiring the replacement of both the horn switch assembly and airbag module cover since the entire airbag module cover must be replaced when replacing a damaged or defective horn switch assembly welded to the airbag module cover. Furthermore, heat staking puts constraints on the design, material and manufacture of the airbag module cover.